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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * iovec manipulation routines.
3 *
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License
7 * as published by the Free Software Foundation; either version
8 * 2 of the License, or (at your option) any later version.
9 *
10 * Fixes:
11 * Andrew Lunn : Errors in iovec copying.
12 * Pedro Roque : Added memcpy_fromiovecend and
13 * csum_..._fromiovecend.
14 * Andi Kleen : fixed error handling for 2.1
15 * Alexey Kuznetsov: 2.1 optimisations
16 * Andi Kleen : Fix csum*fromiovecend for IPv6.
17 */
18
19#include <linux/errno.h>
20#include <linux/module.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070021#include <linux/kernel.h>
22#include <linux/mm.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023#include <linux/net.h>
24#include <linux/in6.h>
25#include <asm/uaccess.h>
26#include <asm/byteorder.h>
27#include <net/checksum.h>
28#include <net/sock.h>
29
30/*
31 * Verify iovec. The caller must ensure that the iovec is big enough
32 * to hold the message iovec.
33 *
Jesper Juhle49332b2005-05-01 08:59:08 -070034 * Save time not doing access_ok. copy_*_user will make this work
Linus Torvalds1da177e2005-04-16 15:20:36 -070035 * in any case.
36 */
37
Maciej Żenczykowski43db3622012-03-11 12:51:50 +000038int verify_iovec(struct msghdr *m, struct iovec *iov, struct sockaddr_storage *address, int mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -070039{
David S. Miller8acfe462010-10-28 11:41:55 -070040 int size, ct, err;
YOSHIFUJI Hideaki4ec93ed2007-02-09 23:24:36 +090041
Linus Torvalds1da177e2005-04-16 15:20:36 -070042 if (m->msg_namelen) {
43 if (mode == VERIFY_READ) {
Namhyung Kima700d8b2010-09-08 03:48:47 +000044 void __user *namep;
45 namep = (void __user __force *) m->msg_name;
46 err = move_addr_to_kernel(namep, m->msg_namelen,
Linus Torvalds1da177e2005-04-16 15:20:36 -070047 address);
48 if (err < 0)
49 return err;
50 }
51 m->msg_name = address;
52 } else {
53 m->msg_name = NULL;
54 }
55
56 size = m->msg_iovlen * sizeof(struct iovec);
Namhyung Kima700d8b2010-09-08 03:48:47 +000057 if (copy_from_user(iov, (void __user __force *) m->msg_iov, size))
Linus Torvalds1da177e2005-04-16 15:20:36 -070058 return -EFAULT;
59
60 m->msg_iov = iov;
61 err = 0;
62
63 for (ct = 0; ct < m->msg_iovlen; ct++) {
David S. Miller8acfe462010-10-28 11:41:55 -070064 size_t len = iov[ct].iov_len;
65
66 if (len > INT_MAX - err) {
67 len = INT_MAX - err;
68 iov[ct].iov_len = len;
69 }
70 err += len;
Linus Torvalds1da177e2005-04-16 15:20:36 -070071 }
72
73 return err;
74}
75
76/*
77 * Copy kernel to iovec. Returns -EFAULT on error.
78 *
79 * Note: this modifies the original iovec.
80 */
YOSHIFUJI Hideaki4ec93ed2007-02-09 23:24:36 +090081
Linus Torvalds1da177e2005-04-16 15:20:36 -070082int memcpy_toiovec(struct iovec *iov, unsigned char *kdata, int len)
83{
84 while (len > 0) {
85 if (iov->iov_len) {
86 int copy = min_t(unsigned int, iov->iov_len, len);
87 if (copy_to_user(iov->iov_base, kdata, copy))
88 return -EFAULT;
89 kdata += copy;
90 len -= copy;
91 iov->iov_len -= copy;
92 iov->iov_base += copy;
93 }
94 iov++;
95 }
96
97 return 0;
98}
Eric Dumazet9e34a5b2010-07-09 21:22:04 +000099EXPORT_SYMBOL(memcpy_toiovec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100
101/*
Michael S. Tsirkin0a1ec072009-04-20 01:25:46 +0000102 * Copy kernel to iovec. Returns -EFAULT on error.
103 */
104
105int memcpy_toiovecend(const struct iovec *iov, unsigned char *kdata,
106 int offset, int len)
107{
108 int copy;
109 for (; len > 0; ++iov) {
110 /* Skip over the finished iovecs */
111 if (unlikely(offset >= iov->iov_len)) {
112 offset -= iov->iov_len;
113 continue;
114 }
115 copy = min_t(unsigned int, iov->iov_len - offset, len);
Sridhar Samudrala2faef522009-06-05 09:35:44 +0000116 if (copy_to_user(iov->iov_base + offset, kdata, copy))
Michael S. Tsirkin0a1ec072009-04-20 01:25:46 +0000117 return -EFAULT;
Sridhar Samudrala2faef522009-06-05 09:35:44 +0000118 offset = 0;
Michael S. Tsirkin0a1ec072009-04-20 01:25:46 +0000119 kdata += copy;
120 len -= copy;
121 }
122
123 return 0;
124}
Eric Dumazet9e34a5b2010-07-09 21:22:04 +0000125EXPORT_SYMBOL(memcpy_toiovecend);
Michael S. Tsirkin0a1ec072009-04-20 01:25:46 +0000126
127/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 * Copy iovec to kernel. Returns -EFAULT on error.
129 *
130 * Note: this modifies the original iovec.
131 */
YOSHIFUJI Hideaki4ec93ed2007-02-09 23:24:36 +0900132
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133int memcpy_fromiovec(unsigned char *kdata, struct iovec *iov, int len)
134{
135 while (len > 0) {
136 if (iov->iov_len) {
137 int copy = min_t(unsigned int, len, iov->iov_len);
138 if (copy_from_user(kdata, iov->iov_base, copy))
139 return -EFAULT;
140 len -= copy;
141 kdata += copy;
142 iov->iov_base += copy;
143 iov->iov_len -= copy;
144 }
145 iov++;
146 }
147
148 return 0;
149}
Eric Dumazet9e34a5b2010-07-09 21:22:04 +0000150EXPORT_SYMBOL(memcpy_fromiovec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151
152/*
Michael S. Tsirkin6f26c9a2009-04-20 01:26:11 +0000153 * Copy iovec from kernel. Returns -EFAULT on error.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154 */
Michael S. Tsirkin6f26c9a2009-04-20 01:26:11 +0000155
156int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov,
157 int offset, int len)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158{
159 /* Skip over the finished iovecs */
160 while (offset >= iov->iov_len) {
161 offset -= iov->iov_len;
162 iov++;
163 }
164
165 while (len > 0) {
166 u8 __user *base = iov->iov_base + offset;
167 int copy = min_t(unsigned int, len, iov->iov_len - offset);
168
169 offset = 0;
170 if (copy_from_user(kdata, base, copy))
171 return -EFAULT;
172 len -= copy;
173 kdata += copy;
174 iov++;
175 }
176
177 return 0;
178}
Eric Dumazet9e34a5b2010-07-09 21:22:04 +0000179EXPORT_SYMBOL(memcpy_fromiovecend);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700180
181/*
182 * And now for the all-in-one: copy and checksum from a user iovec
183 * directly to a datagram
184 * Calls to csum_partial but the last must be in 32 bit chunks
185 *
186 * ip_build_xmit must ensure that when fragmenting only the last
187 * call to this function will be unaligned also.
188 */
189int csum_partial_copy_fromiovecend(unsigned char *kdata, struct iovec *iov,
Al Viro44bb9362006-11-14 21:36:14 -0800190 int offset, unsigned int len, __wsum *csump)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191{
Al Viro44bb9362006-11-14 21:36:14 -0800192 __wsum csum = *csump;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193 int partial_cnt = 0, err = 0;
194
195 /* Skip over the finished iovecs */
196 while (offset >= iov->iov_len) {
197 offset -= iov->iov_len;
198 iov++;
199 }
200
201 while (len > 0) {
202 u8 __user *base = iov->iov_base + offset;
203 int copy = min_t(unsigned int, len, iov->iov_len - offset);
204
205 offset = 0;
206
207 /* There is a remnant from previous iov. */
208 if (partial_cnt) {
209 int par_len = 4 - partial_cnt;
210
211 /* iov component is too short ... */
212 if (par_len > copy) {
213 if (copy_from_user(kdata, base, copy))
214 goto out_fault;
215 kdata += copy;
216 base += copy;
217 partial_cnt += copy;
218 len -= copy;
219 iov++;
220 if (len)
221 continue;
222 *csump = csum_partial(kdata - partial_cnt,
223 partial_cnt, csum);
224 goto out;
225 }
226 if (copy_from_user(kdata, base, par_len))
227 goto out_fault;
228 csum = csum_partial(kdata - partial_cnt, 4, csum);
229 kdata += par_len;
230 base += par_len;
231 copy -= par_len;
232 len -= par_len;
233 partial_cnt = 0;
234 }
235
236 if (len > copy) {
237 partial_cnt = copy % 4;
238 if (partial_cnt) {
239 copy -= partial_cnt;
240 if (copy_from_user(kdata + copy, base + copy,
YOSHIFUJI Hideaki4ec93ed2007-02-09 23:24:36 +0900241 partial_cnt))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242 goto out_fault;
243 }
244 }
245
246 if (copy) {
247 csum = csum_and_copy_from_user(base, kdata, copy,
248 csum, &err);
249 if (err)
250 goto out;
251 }
252 len -= copy + partial_cnt;
253 kdata += copy + partial_cnt;
254 iov++;
255 }
YOSHIFUJI Hideaki4ec93ed2007-02-09 23:24:36 +0900256 *csump = csum;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700257out:
258 return err;
259
260out_fault:
261 err = -EFAULT;
262 goto out;
263}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700264EXPORT_SYMBOL(csum_partial_copy_fromiovecend);